In household cleaning, fabric washing and in many other areas there is a general need for agents which can `bleach` unsightly materials. Agents which `bleach ` normally can react with the unsightly materials to decolorize them. One of the most common of such bleaching agents is sodium hypochlorite, which is widely used in cleaning compositions to decolorize soils, to assist in cleaning through its reaction with soils and to kill micro-organisms.
Sodium hypochlorite is a powerful oxidising agent, which can decolorize a very large number of colored compounds found in soils but which has significant limitations when used to bleach certain fatty and pyrolised soils. There is a need to provide bleaching compositions which can attack these soils. There is also a need to reduce the usage of hypochlorite.
It is known to use oxygen transfer agents such as `imine quat` compounds to promote the bleaching activity of peroxygen compounds. In the context of the present invention, an oxygen transfer agent is a species which reacts with a peroxygen compound such as hydrogen peroxide to form an oxidative bleaching species which oxidative bleaching species, subsequently reacts with a substrate to regenerate the oxygen transfer agent. Such oxygen transfer agents include N-methyl-3,4-dihydroisoquinolinium salts.
U.S. Pat. No. 5,360,569 discloses that imine quat molecules can be used to promote the activity of TAED/perborate bleaching compositions. These systems are believed to work by generating per-acetic acid in situ. This organic peroxide is believed to interact with the imine quat. to bring about the bleaching activity. U.S. Pat. No. 5,360,568 discloses that imine quat molecules can be used to promote the activity of monopersulphate (an inorganic peroxygen compound) and peroxy-adipyl-phthalimide (PAP) (an the organic peracid).